POINCARI, (Jules) Henri, French mathematician and physicist: b. Nancy, 29 April 1854; d. Paris, 17 July 1912. He studied at the teole Polytechnique in 1873 and two years later completed his work at the Ecole Superieur des Mines. In 1879 he received the degree of Doctor of Sciences and took up his residence at Paris, where he soon became prominent at the University. In 1886 he re ceived the appointment of professor of mathe matical physics and calculus of probabilities; and 10 years later succeeded Tisserand in the chair of celestial mechanics. The Academie des Sciences elected him to its membership in 1887 and the Academie Francaise in 1908. Poin care received many prizes for his work, among which may be mentioned the Prix Poncelet (1885) ; the prize awarded by the king of Sweden for the solution of the problem of the three bodies (1889) ; the Prix Reynaud (1896) ; the medal of the Royal Astronomical Society (1900) ; the Sylvester medal of the Royal Society (1901) ; the gold medal of the Lohachevsky Fund (1904) ; the Prix Bolyai (1905), and the gold medal of the Association Francaise pour l'Avancement des Sciences (1909). Poincares principal contributions to mathematical science were along the lines of theory of functions. His researches in physics
were likewise marked by profoundly scientific research, The Fuchsian functions were intro duced into mathematics by him. Among his most important works are (Lecons sur la theorie mathematique de la lumiere' (2 vols., 1889-92) ;
et
(2 vols., 1890-91) ; (Thermodynamique) (1892) ;